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Abstract:

A polarization beam splitter selectively decouples detection light onto a
detector such that it has a polarization direction that differs from the
emitted illumination light. This enables the detection of the light
scattered back in the eye lens at a high level of accuracy, since stray
light from reflections at optical components of the light path is
suppressed. In the generating of photo disruptions or other incisions,
the ray exposure of the retina may be reduced in that the incisions being
furthest away from the laser are induced first such that laminar gas
inclusions with an existence duration time of at least 5 seconds result.
In this manner the laser radiation propagated in the direction of the
retina in further incisions are scattered and partially reflected such
that the influence impinging upon the retina is reduced.

Claims:

1-21. (canceled)

22. An ophthalmological laser system, for the diagnosis of the eye lens
and/or therapy of presbyopia, the ophthalmological laser system
comprising: a laser emitting radiation, the radiation being focusable in
an examination region as illumination light via a beam path; the beam
path, comprising a beam splitter, a scanner unit, and focusing optics,
wherein returning radiation, which returns to the beam splitter from a
direction of the examination region, reaches a detector as detection
light through a confocal aperture diaphragm; and wherein the beam
splitter is a polarization beam splitter, which decouples the detection
light selectively onto the detector such that the detection light
exhibits a polarization direction different from the illumination light.

23. The ophthalmological laser system, according to claim 22, further
comprising an optical phase retardation system positioned in the
illumination beam path between the focusing optics and the examination
region such that the passing illumination light is given a polarization
direction which corresponds with the decoupled detection light.

24. The ophthalmological laser system, according to claim 22, further
comprising a control unit programmed to execute the following:
irradiating of an eye lens, positioned in the examination region, by the
laser with the illumination light at illumination laser power and mapping
of detection light by the detector, directing the scanner unit to scan
the eye lens three-dimensionally, irradiating the eye lens at several
points; and mapping the detection light returned from the eye lens;
determining at least one of form, structure and position of the eye lens
based on the detection light.

25. The ophthalmological laser system, according to claim 24, wherein the
control unit is further programmed to subtract a darkfield value from the
mapped detection light.

26. The ophthalmological laser system, according to claim 24, wherein the
determining at least one of form, structure and position of the eye lens
further includes identifying boundary layers of the eye lens.

27. The ophthalmological laser system, according to claim 24, wherein the
radiation of the laser is, in addition to the illumination laser power,
adjustable to a surgical therapy laser power.

28. The ophthalmological laser system, according to claim 27, wherein the
control unit, after determining at least one of the form, the structure
and the position of the eye lens, is further programmed to execute the
following: determining irradiation control data for a surgical therapy,
wherein the control unit adjusts a basic pattern of the eye lens to at
least one of the determined form and position of the eye lens; and
irradiating the eye lens with a surgical therapy laser power in
accordance with the determined irradiation control data.

29. The ophthalmological laser system, according to claim 28, wherein the
control unit is further programmed to adjust a maximum pulse energy of
0.5 μJ for irradiation with therapy laser power.

30. The ophthalmological laser system, particularly according to claim
28, wherein the control unit determines the irradiation control data such
that, first, an incision furthest from the laser is induced, wherein the
incision is induced such that resulting extensive gas pockets remain in
place for at least 5 seconds.

31. The ophthalmological laser system, according to claim 22, wherein the
control unit is further programmed to immobilize an eye, containing the
eye lens, before the irradiation with illumination laser power by
application of an immobilization device, and after the determination of
the at least one of the form, the structure and the position of the eye
lens or after surgical therapy to release the immobilization of the eye.

32. The ophthalmological laser system, according to claim 22, further
comprising a lock-in amplifier for the detector coupled with the laser.

33. The ophthalmological laser system, according to claim 22, wherein the
laser comprises a pulsed laser and wherein at least one of the beam
splitter, the scanner unit, and the focusing pre-compensate an inherent
dispersion of intraocular media with regard to the pulse length and a
self-focusing effect of a gradient lens structure of the eye lens.

34. A computer implemented operating method for an ophthalmological laser
system, the laser of which is switchable between an illumination laser
power and a therapy laser power, and the laser light of which is
focusable three-dimensionally variably in an eye lens, comprising:
immobilizing an eye containing the eye lens by application of an
immobilization device; irradiating the eye lens, positioned in the
examination region, by application of the laser with an illumination
laser power; scanning the eye lens three-dimensionally by irradiating the
eye lens at several scan points; mapping detection light returned from
the scan points with a detector; determining at least one of form,
structure and position of the eye lens based on the detection light
returned from the scan points; determining irradiation control data for a
surgical therapy, wherein a basic pattern of the eye lens is adjusted to
the determined at least one of the form and position of the eye lens;
irradiating the eye lens by application of the laser with a surgical
therapy laser power in accordance with the determined irradiation control
data; and releasing the immobilization of the eye.

35. The operating method, according to claim 34, further comprising
controlling a scanner unit such that two consecutive scan points differ
from each other in all three spatial coordinates.

36. The operating method, according to claim 34, further comprising
adjusting a pulse frequency of the laser light, dependent on the speed of
scan movement of a focal point of the laser beam relative to the eye
lens.

37. The operating method, according to claim 34, further comprising
subtracting a darkfield value from the mapped detection light.

38. The operating method, according to claim 34, further comprising
identifying boundary layers of the lens for the determination of the at
least one of the form or the position of the eye lens.

39. The operating method, according to claim 38, further comprising
identifying the boundary layers by determining an increase of an
intensity of the detection light between a first focal depth and a second
focal depth and a decrease of the intensity of the detection light
between a third focal depth and a fourth focal depth.

40. The operating method according to claim 34, further comprising
utilizing a maximum pulse energy of 0.5 μJ for irradiation with
therapy laser power.

41. The operating method according to claim 34, further comprising
determining irradiation control data such that, first, an incision
furthest from the laser is induced, wherein said incision is induced such
that the resulting extensive gas pockets remain in place for at least 5
seconds.

Description:

PRIORITY CLAIM

[0001] The present application is a National Phase entry of PCT
Application No. PCT/EP2009/003980, filed Jun. 4, 2009, which claims
priority from German Application Number 102008027358.9, filed Jun. 5,
2008, the disclosures of which are hereby incorporated by reference
herein in their entirety.

FIELD OF THE INVENTION

[0002] The invention relates to an ophthalmological laser system,
particularly for analysis and/or therapy of a presbyopia, with a laser,
the radiation of which is focusable in an examination region as
illumination light via an illumination beam path, which exhibits a beam
splitter, a scanner unit, and focusing optics, whereby radiation, which
reaches the beam splitter from the direction of the examination region,
reaches a detector as detection light through a confocal aperture
diaphragm. Furthermore, the invention relates to an operating method for
an ophthalmological laser system.

BACKGROUND

[0003] Accommodation is the ability of the eye to create a sharp image on
the retina of an object located at any given distance. Thereto, the
required adjustment of the refractive power occurs essentially through
the elastic deformation of the lens. The possible maximum change in
refractive power is called amplitude of accommodation. It can amount to
16 dioptors and decreases with age.

[0004] Presbyopia or age-related farsightedness, i.e., the reduced
amplitude of accommodation of the eye lens, is the result of an
age-related hardening and/or thickening of the eye lens. Typically, an
eye lens is called presbyopic when its amplitude of accommodation drops
below 3 dioptors. Presbyopia is not a pathological process but a natural
consequence of old age, starting at age 40.

[0005] In ophthalmology it has been suggested to restore improved
deformability of a hardened lens through suitable incisions or creation
of bubbles by means of a refractive surgical therapy, particularly
photodisruption or other incisions. Thereby, the accommodative capacity
of the lens is to be partially regenerated.

[0006] Ophthalmological laser systems for presbyopia therapy have already
been described in prior art. For example, WO 2008/017428 A2 discloses a
navigation device for optical analysis and treatment of the inner
structure of the eye lens.

[0007] The navigation device is equipped with a detection device and a
treatment device, whereby the detection device can comprise a confocal
detector and/or a confocal laser scanner. A photomultiplier (PMT) or an
avalanche photodiode (APD) is suggested as detector. The same laser is
provided for the analysis of the inner structure as well as treatment,
whereby the detection beam path is coupled by means of a beam splitter
into the treatment beam path. Thereby, the laser light, backscattered in
the eye lens, is for analysis, in order to determine position, geometry,
and structure of the eye lens. By means of the detected inner structure
and the individual geometric form of the eye lens, the cut geometries to
be produced during treatment are determined. For said purpose, a basic
pattern is adjusted to the detected individual geometry.

[0008] A problem is that the intensity of the light backscattered in the
eye lens is very low due to the inherent properties of the eye lens--for
a high imaging quality, the scatter must be as slight as possible. As a
result, the detection contains a relatively great number of flaws.

SUMMARY OF THE INVENTION

[0009] The invention is based on the task of improving an ophthalmological
laser system of the initially mentioned type in order to allow for the
detection of the light backscattered in the eye lens with increased
accuracy.

[0010] According to the invention, the beam splitter is a polarization
beam splitter, which decouples the detection light on the detector in
such a way that it exhibits a polarization direction different from the
emitted illumination light.

[0011] A large portion of the light, which impinges on the beam splitter
from the examination region, originates from reflections on the optical
components of the beam path, e.g., the surfaces of the focusing optics;
therefore, it exhibits the same polarization direction as the
illumination light. Since the beam splitter only directs light as
detection light to the detector with a different polarization direction,
such stray light is suppressed. However, light backscattered in the eye
lens exhibits an altered polarization direction. Therefore, when compared
to prior art, the detection of the light backscattered in the eye lens is
possible with greater accuracy.

[0012] It is possible to achieve an even greater signal strength, whereby
an optical phase retardation system in the illumination beam path between
the focusing optics and the examination region is arranged in such a way
that the passing illumination light obtains a polarization direction
corresponding to the decoupled detection light. As a result, the stray
light exhibits the same polarization direction as the radiation from the
laser, while the illumination light, which reaches the eye lens and is
modified in the phase retardation system, obtains a defined, different
polarization direction. Through the selection of the light of said
polarization direction as detection light by means of the polarization
beam splitter, only such light, which was backscattered in the eye lens,
is detected almost exclusively. Stray light, which originates from
reflections on optical components, is even more effectively kept away
from the detector.

[0013] In one embodiment, the laser system exhibits a control unit, which
three-dimensionally scans an eye lens, arranged in the examination
region, by means of the laser at illumination laser power, whereby it
irradiates the lens at various points and detects by means of the
detector in the form of detection light from said points and subsequently
determines a form and/or structure and/or position of the eye lens by
means of the detection light. As a result, the form and/or structure
and/or position of the eye lens can be determined with great accuracy.

[0014] Aside from the position of the lens, the location of the eye lens
also comprises, according to the invention, its spatial orientation. The
information regarding the orientation can also be contained in the form
of the eye lens.

[0015] The structure describes the inner configuration of the lens, e.g.,
inclusions or localized alterations, for example, from age-related tissue
modifications or a previous presbyopia therapy.

[0016] In an example embodiment, the control unit subtracts a darkfield
value from the mapped detection light. This can either be a mutual
darkfield value for all scan points or several point-specific darkfield
values. This embodiment allows for a greater accuracy of the imaging of
the light backscattered in the eye lens.

[0017] Advantageously, for the determination of form and/or position of
the eye lens, the control unit identifies one or both boundary layers of
the lens. By means of the drop in backscatter intensity between the
anterior and posterior boundary layer, the boundary layers, and therefore
the form and/or position of the lens, can be determined with great
accuracy. Alternatively or additionally, an image recognition algorithm
can be utilized for identification. It is also possible to have the
boundary layers determined manually by operation personnel. Furthermore,
tissue structures can advantageously be identified within the lens. For
example, the core area (nucleus) and/or the periphery (cortex) can be
detected.

[0018] In an example embodiment, the boundary layers are identified,
whereby an increase of an intensity of the detection light between a
first focal depth and a second focal depth and a decrease of the
intensity of the detection light between a third focal depth and a fourth
focal depth are determined. The anterior and posterior boundary layer are
characterized in that the backscatter during focusing of a scan point in
the boundary layer is significantly higher than during focusing of scan
points outside or inside of the lens. Therefore, the boundary layers can
be identified with little effort by determining an increase or decrease
of the intensity of the detection light.

[0019] In an example embodiment, the radiation of the laser can, in
addition to illumination laser power, be adjusted to a refractive
surgical therapy laser power. As a result, the same laser can be utilized
for the illumination during determination of form/structure/position of
the lens as well as for therapy.

[0020] In said example embodiment, the control unit, after determining
form and/or structure and/or position of the eye lens, preferably
determines the irradiation control data for a refractive surgical therapy
of the eye lens, whereby it adjusts a basic pattern of the eye lens to
the determined form and/or position of the eye lens and irradiates the
eye lens with a refractive surgical therapy laser power in accordance
with the determined irradiation control data. Therefore, analysis of
form/structure/position, and therapy form a direct unit. As a result,
therapy is possible with great accuracy since errors due to a movement of
the eye lens or the patient can be minimized.

[0021] Expediently, the control unit immobilizes an eye containing the eye
lens before irradiation with illumination laser power by means of an
immobilization device and releases the immobilization after the
determination of the form and/or structure and/or position of the eye
lens or after surgical treatment. As a result, the possible changes in
the position of the lens through the patient are minimized, which
increases the accuracy of the analysis and, as the case may be, therapy.

[0022] According to the invention, for the operating method for an
ophthalmological laser system, the laser of which is switchable between
an illumination laser power and a therapy laser power, and the laser
light of which is focusable three-dimensionally variable in an eye lens,
the following steps to be executed are provided: Immobilization of an eye
containing the eye lens by means of an immobilization device; irradiation
of an eye lens, positioned in the examination region, by means of the
laser with illumination laser power and detecting of detection light by
means of a detector, whereby the eye lens is scanned three-dimensionally
through irradiating the eye lens at several points and mapping of
detection light; determination of form and/or structure and/or position
of the eye lens by means of the detection light at the scan points;
determination of irradiation control data for a refractive surgical
therapy, whereby a basic pattern of the eye lens is adjusted to the
determined form and/or position of the eye lens; irradiation of the eye
lens by means of the laser with a refractive surgical therapy laser power
in accordance with the determined irradiation control data; release of
the immobilization of the eye.

[0023] Contrary to refractive surgery on the cornea, it is impossible to
immobilize the eye lens. Only the eye as a whole can be immobilized. The
operating method, according to the invention, solves said problem,
whereby, at first, the eye as a whole is immobilized and the actual
form/structure/position of the lens is subsequently determined. Since the
therapy step follows immediately thereafter and both steps can be
completed in a short period of time, form/structure/position of the lens
for determining the irradiation control data are immediately applied in
the therapy step, rendering an immobilization of the lens unnecessary.
However, for the therapy, a very high accuracy is nevertheless possible.

[0024] In other example embodiments of the laser system, a lock-in
amplifier, coupled with the laser, is provided for the detector. This
allows for the mapping of the detector signals with great accuracy, so
that a possible therapy can also be executed with great accuracy.

[0025] In another example embodiment, the scanning process is effected in
such a way that two consecutive scan points differ from each other in all
three spatial coordinates. Through this type of scanning, a
representative model of the eye lens with regard to
form/structure/position can be obtained in a short period of time. This
allows for decreasing the inaccuracy caused by movements of the lens by
the patient. A control of the scanners in the form of a sine function is
technically particularly advantageous. Controlling the x-y scanners in
such a way that one of the scanners is controlled with exactly double the
frequency than that of the other scanner results in a Lissajous figure,
which resembles the FIG. 8.

[0026] A pulse frequency of the laser light, depending on the motion speed
of a focal point of the laser beam relative to the eye lens, may be
chosen. As a result, the radiation exposure of the lens and the eye
overall can be decreased during analysis and/or particularly during
therapy.

[0027] An additional aspect of the invention relates to the reduction of
the radiation exposure of the retina during the generation of
photodisruptions or other incisions. At first, according to the
invention, one or several extensive incisions in the rearward section of
the eye lens 2 are executed in such a way that extensive gas pockets are
produced, which remain in place for at least 5 seconds. Said gas pockets
or bubbles can be purposefully produced through a suitable selection of
laser parameters, particularly the distance between the irradiation
points and the laser energy. Due to said extensive gas pockets, the laser
radiation, which propagates in the direction of the retina during the
subsequent generation of further incisions in the anterior part of the
eye lens 2, is scattered and partially reflected, resulting in a
reduction of the energy per area (fluence) impinging on the retina.

[0028] In the following, the invention shall be further explained by means
of embodiment examples.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] It is shown in:

[0030]FIG. 1 is an ophthalmological laser system for the analysis of the
eye lens;

[0031] FIG. 2 is an ophthalmological laser system for the analysis and
treatment of the eye lens;

[0035]FIG. 1 shows an exemplary ophthalmological laser system 1 for the
analysis of a presbyopia of an eye lens 2 of an eye 3. The laser system 1
comprises a laser 4, a polarization beam splitter 5, scan optics 6, a
scanner unit 7, focusing optics 8, and an optical phase retardation
system 9, which together form an illumination beam path B; as well as a
deflection mirror 10, a confocal aperture diaphragm 11, and a detector
12, which form a decoupled detection beam path D; and an amplifier 13 and
a control unit 14.

[0036] Between the laser system 1 and the eye 3, a contact glass 17 with
an immobilization device for the eye 3 is positioned, behind which lies
the examination region. Other embodiments for the realization of the
solution, according to the invention, are possible (not depicted).

[0037] For example, the laser 4 is designed as pulsed TiSa infrared laser
with a pulse length between 100 fs and 1000 fs. It emits laser radiation
at an eye-safe illumination laser power in the range of 100 mW. Then
scanner unit 7 comprises, for example, a number of galvanometric mirrors
for the deflection of the laser radiation in the x- and y-directions via
the eye lens 2. The focusing of the laser radiation in z-direction along
the optical axis is effected, e.g., through a movable lens or lens group
within the scan optics 6 or the focusing optics 8, or alternatively
through a movable tube lens (not depicted). The optical phase retardation
system 9, for example, is designed as λ/4 plate, which forms a
border of the laser system. The detector 12, e.g., is designed as
photomultiplier or as APD since the light intensities to be mapped are
low. The amplifier 13 is designed as lock-in amplifier and connected to
the detector 12 as well as the laser 4.

[0038] The pulsed IR laser radiation emerges from the laser 4 and
initially passes unchanged through the polarization beam splitter 5. Then
it is focused via scan optics 6, scanner unit 7, and focusing optics 8 as
illumination light on a scan point P in the eye lens 2. Said scan point P
can be shifted by means of the scanner unit 7 and a movable lens or lens
group within the scan optics 6 or the focusing optics 8 in x-, y-, or
z-direction in the eye lens 2. Thereby, the optical phase retardation
system 9 effects a defined change of the polarization direction of the
illumination light passing through.

[0039] At the boundary layers G1, G1 of the eye lens 2 and the
inhomogeneous layers of the eye lens (not depicted), a
scattering/reflection of the IR radiation occurs, whereby the radiation
is partially depolarized in the eye 3.

[0040] Backscattered/reflected light also impinges on the illumination
beam path B and there returns all the way back to the polarization beam
splitter 5. The radiation components with unchanged polarization status
pass through the polarization beam splitter 5 onto the laser 4. This
refers particularly to reflections which originate from the scan optics 6
or the focusing optics 8. Such radiation components, which, after passing
through the phase retardation system 9 and/or through depolarization in
the eye 3, exhibit a changed polarization status in the eye lens 2, are
deflected by the polarization beam splitter 5 as detection light into the
detection beam path D to the detector 12. The detection light passes via
a deflection mirror 10 through the confocal aperture diaphragm 11 onto
the detector 12. In another embodiment, the deflection mirror 10 can be
omitted or replaced by other beam guidance units. The confocal aperture
11 acts as discriminator in the z-direction, therefore, spatially
resolved, only backscattered light is detected from a low focus volume.
The control unit 14, through the deflection of the illumination light in
x- and y-direction by means of the scanner unit 7 and change of the
focusing in z-direction by means of the focusing optics 8, can irradiate
random scan points P inside and outside of the eye lens 2 with
illumination light and determine the strength of the backscatter at said
points via the intensity of the corresponding detection light.

[0041] In order to determine information about form, structure, and
position of the eye lens 2 with great accuracy in a short period of time,
a suitable spatial distribution of points is scanned. From the hereby
obtained values for the strength of the backscatter, form, inner
structure, and position of the lens can be reconstructed. As a result, a
presbyopia therapy can be performed patient-specific while taking the
lens properties into account. In addition to presbyopia therapy, the
laser system 1 can also be utilized in other ophthalmological
applications, such as the diagnosis of the cornea, in order to gather
information about the eye 3.

[0042] In the depicted embodiment, the optical phase retardation system 9
between the eye 3 and focusing optics 8 effects a defined rotation of the
polarization direction of the passing illumination light, while reflected
stray light, reflected at the optical components, initially maintains the
original polarization direction.

[0043] As a result, the relative intensity of the detection light is
increased since the polarization beam splitter 5 separates any light with
deviating polarization direction as detection light. In alternative
embodiments, the optical phase retardation system 9 can be omitted.
Alternatively or additionally, additional polarizers (not depicted) can
be positioned in the illumination and/or detection beam path in order to
improve the signal quality. In another embodiment, the phase retardation
system can be realized as depolarizer, so that the extent of the phase
retardation varies via the beam profile.

[0044] Since the signals registered at the detector 12 exhibit a very low
intensity, the electronic amplifier is adjusted to an optimized
signal-to-noise ratio. Another example embodiment is the lock-in
amplifier, which is temporally synchronized with the pulse generation
and/or the repetition frequency of the laser 2. Other embodiments, for
example, utilize so-called boxcar techniques or scanning techniques
(sampling) with adding up or averaging. Advantageously, the entire
amplifier system of the detector signal exhibits a nonlinear
characteristic.

[0045] FIG. 2 shows an ophthalmological laser system 1 for combined
analysis and therapy of a presbyopia. It corresponds to a large extent
with the laser system 1 in accordance with FIG. 1, but is additionally
equipped with an attenuator 15, which can be tilted into the illumination
beam path B, and a modulator 16, e.g., an acousto-optical modulator. The
attenuator 15 is used for switching between an illumination laser power
and therapy laser power. Illumination laser power is obtained through the
attenuator 15, tilted into the illumination beam path B, and therapy
laser power is obtained without the attenuator 15. The optical
components, particularly optics 6 and 8, are optimized, corrected, and
synchronized towards the goal of a best possible focus miniaturization.
For example, its optical aberrations are minimized to a high degree,
requiring only a low energy input for a photodisruption. The optical
components are designed in such a way that the inherent dispersion of the
intraocular media with regard to the change of pulse length as well as
the inherent focusing effect of the gradient lens structure of the eye
lens are pre-compensated.

[0046] As a result, the size of the focus volume can be maintained
constant over the entire area of the eye lens and over its entire depth
with an error variance of no more than 10%. Particularly, the focus
volume can be shifted with a tolerance of +/-5 mm within a volume with a
diameter of 7 mm and depth of 10 mm towards the apex of the cornea of the
eye lens 2.

[0047] The control unit 14 executes the operating method as shown in FIG.
3, whereby for an example pure analysis of the eye lens 2 only the
solidly outlined steps S1, S2, S3, and S6 are executed. For an example
presbyopia therapy all steps are executed. Thereby, the laser 4 is
utilized not only for illumination during the detection phase but also
for the treatment of the eye lens 2 during the immediately following
therapy phase.

[0048] At first, the eye of the patient is immobilized, for example,
secured to a contact glass device by means of a vacuum (step S1). In
addition, the head of the patient can also be immobilized. Through a
suitable target, the eye position of the patient can be kept as constant
as possible. Thereby, an adjustable compensation of the angle between
geometric and optical axis of the eye is possible.

[0049] The illumination light at illumination laser power is guided across
the eye lens 2 along an adjustable, continuous, three-dimensional scan
curve or structure, and detection light is mapped (step S2). Thereby, the
pulse frequency, in dependence of the speed of the scan movement, is
adjusted in such a way that a lower pulse frequency results from a slow
scan movement than from a fast scan movement. The backscattered detection
light is assigned sectionally or pointwise to individual points of the
scan curve. Due to the consistency of the scan curve, consecutive scan
points differ with regard to all spatial coordinates. From the detected
signal values, respective darkfield values are advantageously subtracted,
which are determined in a separate calibration phase.

[0050] From the intensities assigned to the scan points, form, structure,
and the position of the eye lens 2 are reconstructed as model (step S3).
Thereto, particularly its boundary layers can be identified, e.g., the
anterior or posterior boundary layer and/or interior areas such as the
junction between cortex and nucleus. For example, the model can represent
the eye lens 2 as gradient lens, i.e., with an interior course of the
refractive index of the lens medium. Particularly, the model can
reproduce a tilting of the eye lens 2 towards the optical axis of the
system 1.

[0051] Said information is used to adjust a basic pattern of the eye lens
and the incisions, predefined by the operator beforehand, to the actual
individual condition of the eye lens 2 in order to determine the
irradiation control data by means of the adjusted basic pattern (step
S4). For example, basic patterns can be spherical surfaces, ellipsoids,
or conic sections, which are adjusted to the reconstructed model, e.g.,
through shifting, tilting, clipping of the boundaries, enlargement or
stretching of the pattern in order to allow for a centering of the
pattern with regard to the real position of the lens in space as well as
an observance of safety zones. The irradiation control data comprise,
e.g., control signals for the axes of the scanner unit and/or the
internal z-focusing, and for the laser beam source and the power
modulator 16.

[0052] Immediately thereafter, by means of the irradiation control data,
the actual refractive surgical procedure is executed with therapy laser
power (step S5). Thereby, for example, one or several photodisruption
bubbles with a maximum pulse energy of preferably 0.5 μA are produced
through the laser radiation at a pulse frequency from 100 kHz to 1 MHz
and a pulse length of less than 1 ps, particularly 300 fs. Thereby, the
radiation exposure of the retina can be reduced, whereby the therapy is
initiated in the posterior area of the eye lens 2, e.g., with the
rearmost incision, before executing additional therapeutic incisions in
the central and anterior area of the eye lens 2. Lastly, the
immobilization of the lens 2 is released (step S6).

[0053] Due to the identical beam path for analysis and therapy, the system
1 is self-calibrating. Since the irradiation control data are determined
by means of the information about form/structure/position of the lens,
obtained with the identical beam path, the therapy allows for great
accuracy.

[0054] Through the use of adjusted scan curves (scan patterns), for
example, in the form of Lissajous figures, the combined procedure can
also be executed in a short period of time, for example, within a maximum
of 30 seconds, which reduces inaccuracies due to movement and leads to
better acceptance by the patient.

[0055]FIG. 4 shows an exemplary scan curve in the form of spatially
offset FIG. 8, which can be realized as a Lissajous figure by means of
the scanner unit 6. It has the advantage of allowing for the
determination of representative data for the reconstruction of a lens
model with great accuracy in a short period of time.

[0056] Other exemplary forms of scanning and/or rastering can be (not
depicted): two crossed rectangles in space; two cylindrical surfaces; a
cylindrical body with a profile in the form of a FIG. 8 or 4; several
scans along one-dimensional lines. It is also possible to raster the
volume of a cylinder or a cube. The volumes and/or surfaces can be
scanned continuously or only partially, i.e., with gaps between the
individual scan points. As a result, greater distances can occur between
individual lines. The scanning structure stretches advantageously from
the boundaries via an area from at least 2.5 mm up to 5 mm axially behind
the contact glass and from at least 0 mm to 4 mm in diameter laterally
with regard to the optical axis of the treatment optics.

[0057] The operating method, according to the invention, can also be
utilized with other laser systems. For example, instead of the confocal
detection, an interferometric measurement of the eye lens can be
provided.